369 research outputs found
Thermodynamics of viscous Matter and Radiation in the Early Universe
Assuming that the background geometry is filled with free gas consisting of
matter and radiation and no phase transitions being occurred in the early
Universe, we discuss the thermodynamics of this {\it closed} system using
classical approaches. We find that essential cosmological quantities, such as
Hubble parameter , scale factor and curvature parameter , can be
derived from this simple model, which on one hand fulfills and entirely obeys
the laws of thermodynamics. On the other hand, the results are compatible with
the Friedmann-Lemaitre-Robertson-Walker model and the Einstein field equations.
The inclusion of finite bulk viscosity coefficient derives to important changes
in all these cosmological quantities. Accordingly, our picture about the
evolution of the Universe and its astrophysical consequences seems to be a
subject of a radical revision. We find that strongly depends on the
thermodynamics of background matter. The time scale, at which negative
curvature might take place, depends on the relation between the matter content
and the total energy. Using quantum and statistical approaches, we assume that
the size of the Universe is given by the volume occupied one particle and one
photon. Different types of their interactions are taken into account.
Expressions for and are introduced. Therefore, the expansion of the
Universe turns to be accessible.Comment: 9 pages, 2 figures (3 eps graphs
Facile synthesis of mesoporous N doped zirconium titanium mixed oxide nanomaterial with enhanced photocatalytic activity under visible light
The present paper deals with a hydrazine mediated synthesis of high surface area and thermally stable
N-doped zirconium titanium mixed oxide with enhanced photocatalytic activity towards reduction of
selenium (VI) to metallic Se0 under visible light. Materials were synthesized at pH ¼ 2 by varying the
hydrazine concentration and characterized by XRD, TEM, BET method, XPS, Raman spectroscopy
and UV-vis solid state spectra. Presence of low amount of zirconium oxide (10 wt%) helps in phase
stabilization and maintains the porous structure even at higher calcinations temperature in comparison
to that of pure titania. XPS spectrum justifies the presence of nitrogen and Ti3+ in the material due to
the decomposition reaction of hydrazine. Hydrazine controls the nitrogen content, surface area and the
formation of oxygen vacancy in the material. Investigation of metal oxide to hydrazine ratio on the
overall surface properties and photocatalytic activity indicates that the 1 : 6 ratio is the optimum
composition for the best result. Surface area and pore volume increases to 298 m2/g and 0.323 cm3/g.
The obtained material (TiZr-6N-400) is found to reduce selenium (VI) to selenium (0) under visible light
within only 45 min of reaction. Increased photocatalytic activity under visible light is mostly due to the
synergistic effect of substantial nitrogen doping, high surface area and presence of oxygen vacancy
Mechanical Behavior of Zr-Based Metallic Glasses and Their Nanocomposites
In the present chapter, results of our recent investigations on the role of gallium (Ga) on the aluminum (Al) site in Zr69.5Al7.5-xGaxCu12Ni11 metallic glass (MG) composition have been discussed. The material tailoring and cooling rate effects on the mechanical behavior of Zr-based metallic glasses and their nanocomposites have been studied. The substitution of Ga on the Al site in Zr–Al–Cu–Ni alloy affects the nucleation and growth characteristics of quasicrystals (QCs) and consequently changes the morphology of nanoquasicrystals. The Zr69.5Al7.5-xGaxCu12Ni11 system displayed metallic glass formation in the range of x = 0–7.5. In this process, we have come out with a new glass composition; Zr-Ga-Cu-Ni with glass transition temperature (Tg)—614 K. The effect of cooling rate on the glass forming ability (GFA) and mechanical properties for this new metallic glass composition has been discussed and compared with some other Zr-based metallic glasses. The various indentation parameters such as microhardness, yield strength, strain hardening constant, nature of shear band formation, and so on for the alloys have been analyzed. The study is focused on investigations of these materials to understand the structure (microstructure) property correlations
Immune Mediated Musculoskeletal Disorders of Dogs: An Overview
Immune mediated musculoskeletal diseases are important diseases of dogs which occur due to failure of immunoregulation or to an abnormal immune response. As clinical signs of these disorders overlap with numerous other syndromes of musculoskeletal system, the confirmative diagnosis is difficult. Glucocorticoids are the basis of therapy with adjunct therapy of cytotoxic drugs, chrysotherapy which require continuous monitoring of patient. Generally there is no curative treatment in most of the disorders due to recurrence of disease after withdrawal of treatment
Additions to wood decaying fungi of India
Three resupinate wood decaying fungi, namely Australohydnum dregeanum, Hjortstamia friesii (Phanerochaetaceae), Schizopora flavipora (Schizoporaceae) are reported for the first time from India. These fungi were collected on stored wood of Anogeissus latifolia, Terminalia tomentosa and Lannea coromandelica from different wood depots of Chhattisgarh, India
Five Dimensional Cosmological Models in General Relativity
A Five dimensional Kaluza-Klein space-time is considered in the presence of a
perfect fluid source with variable G and . An expanding universe is
found by using a relation between the metric potential and an equation of
state. The gravitational constant is found to decrease with time as whereas the variation for the cosmological constant follows as
, and
where is the equation of state parameter and is the scale factor.Comment: 13 pages, 4 figures, accepted in Int. J. Theor. Phy
The key to the future lies in the past: Insights from grain legume domestication and improvement should inform future breeding strategies
Crop domestication is a co-evolutionary process that has rendered plants and animals significantly dependent on human interventions for survival and propagation. Grain legumes have played an important role in the development of Neolithic agriculture some 12,000 years ago. Despite being early companions of cereals in the origin and evolution of agriculture, the understanding of grain legume domestication has lagged behind that of cereals. Adapting plants for human use has resulted in distinct morpho-physiological changes between the wild ancestors and domesticates, and this distinction has been the focus of several studies aimed at understanding the domestication process and the genetic diversity bottlenecks created. Growing evidence from research on archeological remains, combined with genetic analysis and the geographical distribution of wild forms, has improved the resolution of the process of domestication, diversification and crop improvement. In this review, we summarize the significance of legume wild relatives as reservoirs of novel genetic variation for crop breeding programs. We describe key legume features, which evolved in response to anthropogenic activities. Here, we highlight how whole genome sequencing and incorporation of omics-level data have expanded our capacity to monitor the genetic changes accompanying these processes. Finally, we present our perspective on alternative routes centered on de novo domestication and re-domestication to impart significant agronomic advances of novel crops over existing commodities. A finely resolved domestication history of grain legumes will uncover future breeding targets to develop modern cultivars enriched with alleles that improve yield, quality and stress tolerance
Global gene expression analysis of pigeonpea with male sterility conditioned by A 2 cytoplasm
Cytoplasmic male sterility(CMS), a maternally inherited trait, provides a promising means to harness yield gains associated with hybrid vigor. In pigeonpea [Cajanus cajan (L.) Huth], nine types of sterility-inducing cytoplasm have been reported, of which A2 and A4 have been successfully deployed in hybrid breeding. Unfortunately, molecular mechanism of the CMS trait is poorly understood because of limited research invested. More recently, an association between a mitochondrial gene (nad7) and A4-CMS has been demonstrated in pigeonpea; however, the mechanism underlying A2-CMS still remains obscure. The current investigation aimed to analyze the differences in A2-CMS line (ICPL 88039A) and its isogenic maintainer line (ICPL 88039B) at transcriptome level using next-generation sequencing. Gene expression profiling uncovered a set of 505 genes that showed altered expression in response to CMS, of which, 412 genes were upregulated while 93 were downregulated in the fertile maintainer line vs. the CMS line. Further, gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and protein–protein interaction (PPI) network analyses revealed association of CMS in pigeonpea with four major pathways: glucose and lipid metabolism, ATP production, pollen development and pollen tube growth, and reactive oxygen species (ROS) scavenging. Patterns of digital gene expression were confirmed by quantitative real-time polymerase chain reaction (qRT-PCR) of six candidate genes. This study elucidates candidate genes and metabolic pathways having potential associations with pollen development and male sterility in pigeonpea A2-CMS. New insights on molecular mechanism of CMS trait in pigeonpea will be helpful to accelerate heterosis utilization for enhancing productivity gains in pigeonpea
Breeding more crops in less time: A perspective on speed breeding
Breeding crops in a conventional way demands considerable time, space, inputs for selection, and the subsequent crossing of desirable plants. The duration of the seed-to-seed cycle is one of the crucial bottlenecks in the progress of plant research and breeding. In this context, speed breeding (SB), relying mainly on photoperiod extension, temperature control, and early seed harvest, has the potential to accelerate the rate of plant improvement. Well demonstrated in the case of long-day plants, the SB protocols are being extended to short-day plants to reduce the generation interval time. Flexibility in SB protocols allows them to align and integrate with diverse research purposes including population development, genomic selection, phenotyping, and genomic editing. In this review, we discuss the different SB methodologies and their application to hasten future plant improvement. Though SB has been extensively used in plant phenotyping and the pyramiding of multiple traits for the development of new crop varieties, certain challenges and limitations hamper its widespread application across diverse crops. However, the existing constraints can be resolved by further optimization of the SB protocols for critical food crops and their efficient integration in plant breeding pipelines
Simplifying the mosaic description of DNA sequences
By using the Jensen-Shannon divergence, genomic DNA can be divided into
compositionally distinct domains through a standard recursive segmentation
procedure. Each domain, while significantly different from its neighbours, may
however share compositional similarity with one or more distant
(non--neighbouring) domains. We thus obtain a coarse--grained description of
the given DNA string in terms of a smaller set of distinct domain labels. This
yields a minimal domain description of a given DNA sequence, significantly
reducing its organizational complexity. This procedure gives a new means of
evaluating genomic complexity as one examines organisms ranging from bacteria
to human. The mosaic organization of DNA sequences could have originated from
the insertion of fragments of one genome (the parasite) inside another (the
host), and we present numerical experiments that are suggestive of this
scenario.Comment: 16 pages, 1 figure, Accepted for publication in Phys. Rev.
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